Currently, unmanned ground sensors are positioned in remote locations. The sensors collect information and data related to weather and ground conditions. And, these ground sensors can detect physical activity such as movement of vehicles, individuals and animals in a defined area. With appropriate antenna systems, these sensors are also capable of transmitting the collected information to a centralized location by transmitting signals to a nearby ground station, over-flying aircraft, or even satellites. The antenna system functions as part of the overall sensor to detect the aforementioned movements and nearby electrical communications. It will also be appreciated that these unmanned sensors can be re-programmed to monitor other characteristics as needed, or the sensors can be turned off remotely if their use is no longer required.
The most effective sensors are believed to be those that are not easily detected. For example, sensors used for military purposes must be inconspicuous and not easily detected. In other words, it is desirable for the sensor and antenna to be small and adaptable to various environmental settings. It is also important for such a sensor and associated antenna to be electrically quiet so as to avoid detection by other sensors.
Skilled artisans will appreciate that these devices must be able to operate in selected frequency ranges and also operate in multiple frequency ranges. Unfortunately, such antennas known in the art can be quite sizeable and easily detected, thereby defeating their purpose. Therefore, there is a need in the art for a multiband antenna to be small, compact, easily concealed, and capable of operating on multiple and select frequency ranges. And there is a need for the sensor and associated antenna to operate in an electrically quiet manner.